I've never had a chain come off of my "Ghost Racer 7G" with the 49cc 4-stroke and before I even ordered the kit over 3 years ago I ordered the 1.5" CNC Hub Adapter for my Micargi Touch and a 36 tooth CNC sprocket. Throw away the rag mount which clamps to the spokes, a NO NO. I ordered mine from ManicMechanic. GasBike and Kings Motorized Bikes also has these parts. The Hub Adapter is the way to go.